diff --git a/swh/perfecthash/hash.h b/swh/perfecthash/hash.h
index 98d7551..e1c074d 100644
--- a/swh/perfecthash/hash.h
+++ b/swh/perfecthash/hash.h
@@ -1,59 +1,59 @@
 /*
  * Copyright (C) 2021-2022  The Software Heritage developers
  * See the AUTHORS file at the top-level directory of this distribution
  * License: GNU General Public License version 3, or any later version
  * See top-level LICENSE file for more information
  */
 
 #include <cmph.h>
 #include <cmph_types.h>
 #include <stdint.h>
 
 #define SHARD_OFFSET_MAGIC 32
 #define SHARD_OFFSET_HEADER 512
-#define SHARD_KEY_LEN 20
+#define SHARD_KEY_LEN 32
 extern const int shard_key_len;
 
 #define SHARD_MAGIC "SWHShard"
 #define SHARD_VERSION 1
 
 typedef struct {
     uint64_t version;
     uint64_t objects_count;
     uint64_t objects_position;
     uint64_t objects_size;
     uint64_t index_position;
     uint64_t index_size;
     uint64_t hash_position;
 } shard_header_t;
 
 typedef struct {
     char key[SHARD_KEY_LEN];
     uint64_t object_offset;
 } shard_index_t;
 
 typedef struct {
     char *path;
     FILE *f;
     shard_header_t header;
     cmph_t *hash;
 
     // The following fields are only used when creating the Read Shard
     cmph_io_adapter_t *source;
     cmph_config_t *config;
     shard_index_t *index;
     uint64_t index_offset;
 } shard_t;
 
 shard_t *shard_init(const char *path);
 int shard_destroy(shard_t *shard);
 
 int shard_create(shard_t *shard, uint64_t objects_count);
 int shard_object_write(shard_t *shard, const char *key, const char *object,
                        uint64_t object_size);
 int shard_save(shard_t *shard);
 
 int shard_load(shard_t *shard);
 int shard_lookup_object_size(shard_t *shard, const char *key,
                              uint64_t *object_size);
 int shard_lookup_object(shard_t *shard, char *object, uint64_t object_size);